One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,5)(4,6)(7,8)(9,10,15,20,16,22,14,21)(11,23,25,17,26,37,29,36)(12,27,24,18,31,38,30,39)(13,32,33,19,28,35,34,40)(1,3,4,7)(2,5,6,8)(9,11,14,29,16,26,15,25)(10,17,21,23,22,36,20,37)(12,28,30,33,31,13,24,34)(18,32,27,40,39,35,38,19)(2,6)(3,7)(9,12,14,30,16,31,15,24)(10,18,20,38,22,39,21,27)(11,13,29,34,26,28,25,33)(17,35,37,40,36,32,23,19)(9,13)(10,19)(11,24)(12,29)(14,34)(15,33)(16,28)(17,18)(20,35)(21,32)(22,40)(23,27)(25,31)(26,30)(36,39)(37,38) involution — undirectedA Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.